Large array, small battery bank.

[Chispas]

Despite being off grid for years, having bodged together several tiny 12 V systems, I realise that I am, in fact, a beginner. Im in the learning & thinking about it phase of planning a new system, the main objective being to retire our propane fridge/freezer.
What ive sketched out so far is our current energy use - at an absolute maximum 0.5 Kwh - & proposed future use with a fridge/freezer & maybe a small chest freezer at 1.5 Kwh.
We have a budget of €2000 but thats not a hard ceiling. Having said that, I'm not in the habit of chucking money at projects. To that end, I've thought about a 200AH 24 V LiFePo4 battery & Victron SCC 7 1200 W inverter. One idea that appeals to me is redundancy, having 2 strings with 2 SCCs & a large array, cos panels are cheap & we get changeable weather here sometimes.but what about charging rates for LFP ? the Li Time specs for their 200ah says recommended charge rate at 40 A ??? What are the practical limits for a big array & small battery bank? Should I just overpanel a smaller SCC?

 

[Brucey]

So with a Victron smart solar SCC it's trivial to limit the SCC to something below it's max amperage. Can you clarify what this is "Victron SCC 7 1200 W inverter"

On a more complex system one can use a Cerbo or pi running venus os to enable DVCC, that allows you to put a max charge limit in place, yet it will also power loads with any excess production beyond your battery charge limit.

When I first started dabbling in Victron I had a 150/35, then got a second for redundancy and more capacity. Generally the pricing per watt of charger with Victron is similar so there's no major savings as such in getting a 150/70 over two 150/35s and then you have two separate strings for flexibility in location, shading etc.

 

[Q-Dog]

The Victron SCCs allow you to set the output current at less than the unit rating. And if you use a shunt and GX device you can use DVCC to limit charging to batteries, but it will raise SCC output when a load is applied to the system.

 

[Q-Dog]

Looks like Brucey and I think alike, but his words are more gooder than mine today.

 

[Brucey]

Looks like Brudey and I think alike, but his words are more gooder than mine today.

We all strive to do betterer

 

[mactech]

We all strive to do betterer

OK Brudey

 

[Chispas]

"Victron SCC 7 1200 W

sorry fat finger typing Victron charge controller & 1200 W inverter

 

[Chispas]

So with a Victron smart solar SCC it's trivial to limit the SCC to something below it's max amperage.

To match with the maximun Aps for the battery, thanks.

And if you use a shunt and GX device you can use DVCC to limit charging to batteries, but it will raise SCC output when a load is applied to the system.

That sounds great but GX for such a small system ? maybe just do it with the SCC ?

 

[Brucey]

sorry fat finger typing Victron charge controller & inverter

Ah ok, so the 24/1200 multiplus assuming you are in 240V land? Should be a nice unit.

Here in the US they only just recently released the 12/500 and 12/1200 multiplus, no idea if the other models and 24 and 48V units will also come one day.

I have a regular Pheonix 48/1200, it's very impressive capability in terms of surge performance, low idle use, and really not a lot of money at $330. The 12/1200 multiplus goes for around $490, and of course that gives you the 50A charger and transfer switch etc so pretty solid bang for buck.

 

[Q-Dog]

To match with the maximun Aps for the battery, thanks.

That sounds great but GX for such a small system ? maybe just do it with the SCC ?

I only spent about $100 for the Raspberry Pi and cables, and VenusOS is free. If you are fully off grid and rely on your system for all power I would think the ability to use VRM monitoring anywhere in the world is worth the price. All of the other benefits of a GX device are just extra. I really like DVCC, lets me be gentle on the batteries and still use full output of the chargers to run large loads during the day.

 

[Chispas]

I only spent about $100 for the Raspberry Pi and cables, and VenusOS is free.

That might be a better route but my installation is remote, we run 220 AC down to the cabin from the shed which is out of range for WiFi.

 

[cs1234]

I really like DVCC, lets me be gentle on the batteries and still use full output of the chargers to run large loads during the day.

If you had even more batteries, you could use more charge current and still be gentle to all of them. Just get more batteries.

 

[Chispas]

Ah ok, so the 24/1200 multiplus

no, just the Phoenix 24/1200, trying to stay within budget. Ive looked at a multiplus 800W that has a peak of 1600 W & the Phoenix is 2200. Im thinking of a fridge freezer & chest freezer starting at the same time. Mutiplus or compact inverters are 2 x the price of the small phoenix 1200.Not sure what the multiplus does for the extra € ?

 

[Chispas]

If you had even more batteries, you could use more charge current and still be gentle to all of them. Just get more batteries.

what for ? Im trying not to build a massive system for a daily consumption of 1.5 Kwh .

 

[cs1234]

what for ? Im trying not to build a massive system for a daily consumption of 1.5 Kwh .

That was directed @Q-Dog .. as a joke that we always need more batteries, because we are sick addicts. But, now that you mention it, you should get more batteries too!

 

[Q-Dog]

That might be a better route but my installation is remote, we run 220 AC down to the cabin from the shed which is out of range for WiFi.

The Raspberry Pi is connected to our network with a cable, not WiFi. The only wireless connection it has is a bluetooth connection to a Ruuvi tag about 5 feet away.

 

[Brucey]

no, just the Phoenix 24/1200, trying to stay within budget. Ive looked at a multiplus 800W that has a peak of 1600 W & the Phoenix is 2200. Im thinking of a fridge freezer & chest freezer starting at the same time. Mutiplus or compact inverters are 2 x the price of the small phoenix 1200.Not sure what the multiplus does for the extra € ?

The multiplus adds an integrated charger and transfer switch, I e. you can plug it into the wall and it will act as UPS with pass through, charge from gen etc. I had a full size fridge freezer, and a 7 and 21 cuft freezer plus a bunch of other stuff on my 48/1200. I wouldn't go lower, especially if one goes into a defrost cycle.

 

[Chispas]

you can plug it into the wall and it will act as UPS

Except the nearest wall with mains power is some KMs away ;-) Agree with the comments about inverter size, its good to have some spare capacity. The Phoenix 24/1200 retails at €350, add a blue smart IP22 charger for €200 & you've got a good saving on a multiplus 24/1200 at about €800. Victrons overlapping range of products & pricing structure is a great example of how to build upselling into your business. This is how [people go from "maybe i should buy a small trailer to haul stuff to the dump, keep the dirt out of my car" to " hey folks I'm the proud owner of a brand new F 450 super duty" I've seen a lot of this in 4x4 forums ;-)

 

[Brucey]

Except the nearest wall with mains power is some KMs away ;-) Agree with the comments about inverter size, its good to have some spare capacity. The Phoenix 24/1200 retails at €350, add a blue smart IP22 charger for €200 & you've got a good saving on a multiplus 24/1200 at about €800. Victrons overlapping range of products & pricing structure is a great example of how to build upselling into your business. This is how [people go from "maybe i should buy a small trailer to haul stuff to the dump, keep the dirt out of my car" to " hey folks I'm the proud owner of a brand new F 450 super duty" I've seen a lot of this in 4x4 forums ;-)

Well instead of grid think generator. the ip22 range maxes out with their 16A charger. the 24/1200 multi has a 25A integrated charger. Maybe the UK pricing delta is different, when I looked at US pricing the 12/1200 multiplus with integrated 50A charger was a fair bit cheaper than the Phoenix 12/1200 plus the Victron 50A 12V charger.

Victron Energy, PMP242120000, MultiPlus 24/1200/25 - Inverter Supply Renewable Energy Source

Victron Energy, PMP242120000, MultiPlus 24/1200/25 - Note: *** This Product Is 230 VAC Output, European Voltage, Not For Use In The U.S.A ***The new style MultiPlus is set to replace the earlier MultiPlus Compact range. It

www.invertersupply.com

Don't get me wrong, I started with 12V 100Ah lfps and an ip22 12/30 charger as additional battery expansion for my river 2s. Rock solid and plenty of configuration. But I'd have gone with a multiplus 1200 if one had been available for the additional functionality for less in the case of the 12/1200.

 

[Chispas]

Well instead of grid think generator. the ip22 range maxes out with their 16A charger. the 24/1200 multi has a 25A integrated charger. Maybe the UK pricing delta is different

Im in Spain mate but UK prices are the same. I have thought about the 16A capacity of the ip22, its a bit short for a 200 AH battery. The smaller mulitiplus has a 40 A charger, so it might be worth a look. Last winter we ran the generator about 3 or 4 times for battery charging, we have a Sterling Pro charge 50A & FLA so its not running very long, that thing is just stuffing the current in. The prospect of runny the genny for hours isnt appealing, its got a 5l tank & i dont fancy hot refuelling. The other issue is standby consumption, ill have to take a look, but I think the smaller Multiplus has an eco or search mode & uses about 3 W. Yep the bigger chargers are serious money so ill have to give this some serous thought, but the worst case scenario with the smaller charger is running the generator for some hours.
The US price for the multiplus is seriously cheap BTW.

 

[Chispas]

Well instead of grid think generator. the ip22 range maxes out with their 16A charger. the 24/1200 multi has a 25A integrated charger. Maybe the UK pricing delta is different, when I looked at US pricing the 12/1200 multiplus with integrated 50A charger was a fair bit cheaper than the Phoenix 12/1200 plus the Victron 50A 12V charger.

Victron Energy, PMP242120000, MultiPlus 24/1200/25 - Inverter Supply Renewable Energy Source

Victron Energy, PMP242120000, MultiPlus 24/1200/25 - Note: *** This Product Is 230 VAC Output, European Voltage, Not For Use In The U.S.A ***The new style MultiPlus is set to replace the earlier MultiPlus Compact range. It

www.invertersupply.com

Don't get me wrong, I started with 12V 100Ah lfps and an ip22 12/30 charger as additional battery expansion for my river 2s. Rock solid and plenty of configuration. But I'd have gone with a multiplus 1200 if one had been available for the additional functionality for less in the case of the 12/1200.

What have I done ? I saw a multiplus 24/1200 25 at an even better price than your link so i pulled the trigger

I usually order from Autosolar, probably the biggest supplier in Spain because they're so easy to deal with, will actually respond to Emails in minuites during the working day, but the prices are high. Autosolar will also deliver within 48 hours, but the place I order from said 3 - 8 working days.....

The blue madness begins....

​

 

[Brucey]

What have I done ? I saw a multiplus 24/1200 25 at an even better price than your link so i pulled the trigger

I usually order from Autosolar, probably the biggest supplier in Spain because they're so easy to deal with, will actually respond to Emails in minuites during the working day, but the prices are high. Autosolar will also deliver within 48 hours, but the place I order from said 3 - 8 working days.....

The blue madness begins....

​

 

[Brucey]

sorry fat finger typing Victron charge controller & 1200 W inverter

So only the 450/100 and 200 have two mppt trackers, the smaller units are single tracker.

 

[Chispas]

the smaller units are single tracker.

im looking at a 4 panel, 2 x SCCs set up for some redundancy, using the 100/30 smart. I dont think that 2 trackers are essential ?

 

[Brucey]

im looking at a 4 panel, 2 x SCCs set up for some redundancy, using the 100/30 smart. I dont think that 2 trackers are essential ?

ok yeah that's fine, you have two trackers and redundancy there.